getopt

- parse command options

Synopsis

set-– ` getopt optstring $ * `

Description

The getopts command supersedes getopt. For more information, see NOTES below.

getopt is used to break up options in command lines for easy
parsing by shell procedures and to check for legal options. optstring is
a string of recognized option letters; see getopt(3C). If a letter is
followed by a colon (:), the option is expected to have an
argument which may or may not be separated from it by white
space. The special option – is used to delimit the end of the
options. If it is used explicitly, getopt recognizes it; otherwise, getopt generates
it; in either case, getopt places it at the end of the
options. The positional parameters ($1 $2 . . . ) of the shell are reset so that
each option is preceded by a - and is in its own
positional parameter; each option argument is also parsed into its own positional
parameter.

Examples

Example 1 Processing the arguments for a command

The following code fragment shows how one might process the arguments for
a command that can take the options -a or -b, as well
as the option -o, which requires an argument:

See Also

Diagnostics

getopt prints an error message on the standard error when it encounters
an option letter not included in optstring.

Notes

getopt will not be supported in the next major release. For this
release a conversion tool has been provided, namely, getoptcvt. For more information,
see getopts(1) and getoptcvt(1).

Reset optind to 1 when rescanning the options.

getopt does not support the part of Rule 8 of the command
syntax standard (see Intro(1)) that permits groups of option-arguments following an option
to be separated by white space and quoted. For example,

cmd -a -b -o "xxx z yy" filename

is not handled correctly. To correct this deficiency, use the getopts command
in place of getopt.

If an option that takes an option-argument is followed by a value
that is the same as one of the options listed in optstring
(referring to the earlier EXAMPLES section, but using the following command line:

cmd -o -a filename

getopt always treats it as an option-argument to -o; it never recognizes
-a as an option. For this case, the for loop in the
example shifts past the filename argument.